In reply to zakmacro:
In the words of the Village People, go west.
Wyoming will probably be good, hot, but Devil's Tower always has shade somewhere. The Tetons are an alpine range on the other side of the state, perfect for that.
Further south to Colorado and S Dakota etc and it might be too hot. I have been to Yosemite around then and it was bearable, Tuolomne Meadows nearby will be perfect though. The deserts and J-Tree etc won't be bearable. You could head into the high sierras though.
You might get a better response in Rock Destinations. And being more specific will help too, it's a big place.